WO2019088469A1

WO2019088469A1 - Developing system with developer recovery

Info

Publication number: WO2019088469A1
Application number: PCT/KR2018/011720
Authority: WO
Inventors: Shinichiro Suzukawa; Yuya Kato
Original assignee: Hp Printing Korea Co., Ltd.
Priority date: 2017-10-31
Filing date: 2018-10-04
Publication date: 2019-05-09
Also published as: JP2019082642A

Abstract

A developing system includes a developing device and a developer recovery device to recover the developer while the developer recovery device is connected to the developing device. A developer discharge port discharges the developer to the developer recover device, and a shutter adjusts an opening area of the developer discharge port by performing an opening/closing operation. The developing system further includes a drive mechanism to actuate the shutter to perform the opening/closing operation.

Description

DEVELOPING SYSTEM WITH DEVELOPER RECOVERY

A developing device that uses a two-component developer may be used in electrophotography. A new developer is supplied into a developer storage chamber in the developing device, and the developing device discharges an old developer from a developer discharge port. The discharged developer is recovered in the developer recovery device.

FIG. 1 is a diagram illustrating the schematic structure of an example imaging apparatus.

FIG. 2 is a cross-sectional view illustrating the schematic structure of an example developing device.

FIG. 3 is a perspective view illustrating a state in which the example developing device of FIG. 2 is connected to a developer recovery device.

FIG. 4 is a schematic diagram illustrating a connecting portion between the developing device and the developer recovery device of FIG. 3 in a first operating position.

FIG. 5 is a schematic cross-sectional view of the connecting portion between the developing device and the developer recovery device of FIG. 4.

FIG. 6 is a schematic diagram illustrating the connecting portion between the developing device and the developer recovery device of FIG. 3 in a second operating position.

FIG. 7 is a schematic cross-sectional view of the connecting portion between the developing device and the developer recovery device of FIG. 6.

FIG. 8 is a schematic cross-sectional view of the connecting portion between another example developing device and an example developer recovery device in a first operating position.

FIG. 9 is a schematic cross-sectional view of the connecting portion between the developing device and the developer recovery device of FIG. 8 in a second operating position.

FIG. 10 is another schematic cross-sectional view of the connecting portion between the developing device and the developer recovery device of FIG. 8.

FIG. 11 is a cross-sectional view illustrating an example shutter.

FIG. 12 is a cross-sectional view illustrating another example shutter.

FIG. 13 is a cross-sectional view illustrating yet another examle shutter.

FIG. 14 is a cross-sectional view illustrating a further example shutter.

In the following description, with reference to the drawings, the same reference numbers are assigned to the same components or to similar components having the same function, and overlapping description is omitted.

For developing systems that recover a developer which is discharged from a developing device, a developer recovery device may be used to recover the developer. In some examples, the developing device is connected to the developer recovery device.

In developing devices that include a developer discharge port, a developer which is scattered in a developer storage chamber may be unintentionally discharged. For example, the developer may be discharged with the flow of air from the developer discharge port due to an increase in internal pressure or the like during the operation of the developing device, resulting in an excessive discharge of the developer from the developing device.

An example developing system includes a developing device and a developer recovery device to recover the developer, which is discharged from the developing device. The developer may be recovered at the developer recovery device in a state in which the developing device is connected to the developer recovery device. The developing device includes a case that stores the developer, and a shutter that performs an opening/closing operation. The developing device or the developer recovery device includes a drive mechanism that allows the shutter to perform the opening/closing operation.

The case is provided with a developer discharge port that discharges the developer stored in the case to the developer recovery device. The shutter may adjust the opening area of the developer discharge port by performing the opening/closing operation. The drive mechanism adjusts the opening area of the developer discharge port by allowing the shutter to perform the opening/closing operation in a state in which the developing device is connected to the developer recovery device.

The developing system can allow the shutter to perform the opening/closing operation even in a state in which the developing device is connected to the developer recovery device. That is, the opening area of the developer discharge port may be adjusted according to the operating state of the developing device, to adjust the opening area of the developer discharge port according to various situations. The developing system can suppress the excessive discharge of the developer from the developing device, which occurs with the flow of air, by adjusting the opening area of the developer discharge port as described in further detail herein.

In the developing system, the case is provided with a first storage portion that stores the developer, which is discharged from the developer discharge port, at a position on an upstream side of the developer discharge port in a discharge direction. The developer discharge port may discharge the developer stored in the first storage portion to the developer recovery device. The developer can be temporarily stored in the first storage portion before being discharged from the developer discharge port. Accordingly, even in a case in which the developer discharge port is closed by the shutter (the opening area is small), the clogging of the case with the developer can be suppressed.

In some examples, the developer recovery device includes a second storage portion that stores the developer discharged from the developing device connected to the developer recovery device, a shutter that performs an opening/closing operation, and a drive mechanism that allows the shutter to perform the opening/closing operation.

The second storage portion is provided with a developer discharge port that discharges the developer stored in the second storage portion into a recovery space of the developer recovery device. The shutter may adjust the opening area of the developer discharge port by performing the opening/closing operation. The drive mechanism adjusts the opening area of the developer discharge port by allowing the shutter to perform the opening/closing operation in a state in which the developing device is connected to the developer recovery device.

The developing system can allow the shutter to perform the opening/closing operation even in a state in which the developing device is connected to the developer recovery device. That is, the opening area of the developer discharge port may be adjusted according to the operating state of the developing device, to adjust the opening area of the developer discharge port according to a situation.

The developing system can suppress the excessive discharge of the developer from the developing device, which occurs with the flow of air, by adjusting the opening area of the developer discharge port. Further, the developer can be temporarily stored in the second storage portion before being discharged from the developer discharge port. Accordingly, even in a case in which the developer discharge port is closed by the shutter (the opening area is small), the clogging of the case with the developer can be suppressed.

In the developing system, the drive mechanism may switch an open/closed state of the shutter to a developer non-discharge mode and a developer discharge mode. The developer non-discharge mode is a mode in which the opening area of the developer discharge port is set to a first opening area in a state in which the developing device is connected to the developer recovery device. The developer discharge mode is a mode in which the opening area of the developer discharge port is set to a second opening area larger than the first opening area in a state in which the developing device is connected to the developer recovery device. Since the open/closed state of the shutter can be switched to two modes even in a state in which the developing device is connected to the developer recovery device, an excessive discharge of the developer from the developing device may be suppressed.

The developing device may include a conveying member that circulates the developer in the developing device. In a case in which the rotational speed of the conveying member in the developer discharge mode is denoted by V1 and the rotational speed of the conveying member in the developer non-discharge mode is denoted by V2, "V1 ≤ V2" may be satisfied. Since much air is taken into the developing device in a case in which the rotational speed of the conveying member is high, the internal pressure of the developing device is increased and the developer may be excessively discharged from the developer discharge port together with the flow of air. The excessive discharge of the developer from the developing device may be suppressed by reducing the opening area in a case in which the rotational speed of the conveying member is high.

In some examples, the drive mechanism may allow the shutter to perform the opening/closing operation by own weight of the developer gathered on the shutter. Accordingly, a driving source for driving the shutter may be omitted, and the developing system can be simplified.

The developing system may further include a storage-amount detection sensor that detects the amount of the developer stored in the first storage portion. The drive mechanism may allow the shutter to perform the opening/closing operation on the basis of a detection result of the storage-amount detection sensor. Further, the developing system may include a storage-amount detection sensor that detects the amount of the developer stored in the second storage portion. The drive mechanism may allow the shutter to perform the opening/closing operation on the basis of a detection result of the storage-amount detection sensor. Since the developer can be discharged according to the amount of the stored developer in the developing system, clogging caused by the developer is suppressed.

In a case in which the developing device stops driving, the drive mechanism may allow the shutter to be operated so that the opening area of the developer discharge port is larger than the opening area of the developer discharge port obtained immediately before the developing device stops driving. In a case in which the developing device stops driving, the internal pressure of the developing device becomes lower than that in a case in which the developing device is being driven. For this reason, the developer may not be excessively discharged together with the flow of air. Accordingly, the developing system can discharge an old developer while suppressing the excessive discharge of the developer by increasing the opening area of the developer discharge port in a case in which the developing device stops driving.

In a case in which the developing device starts driving, the drive mechanism may allow the shutter to be operated so that the opening area of the developer discharge port is smaller than the opening area of the developer discharge port obtained at the time of stop of the driving of the developing device. In a case in which the developing device starts driving, the internal pressure of the developing device becomes higher than that in a case in which the developing device is stopping. For this reason, the developer may be excessively discharged together with the flow of air. Accordingly, the developing system can suppress the excessive discharge of the developer by reducing the opening area of the developer discharge port in a case in which the developing device starts driving.

In some examples, a surface of the shutter corresponding to an upstream side in a discharge direction of the developer may be formed in a tapered shape, the shape of a bowl, or the shape of a flat plate. The developing system can reduce the amount of the developer remaining on the shutter, that is, can appropriately discharge the developer in a case in which the shutter is in an open state.

A pressure-release hole may be used to adjust pressure in the case. The pressure-release hole may be covered with a filter. Since an increase in the internal pressure of the case of the developing device can be suppressed, the excessive discharge of the developer from the developing device can be suppressed.

In some examples, a plurality of the developing devices are connected to the developer recovery device. The shutter and the drive mechanism are provided for each of the plurality of developing devices. The plurality of drive mechanisms may allow the shutters to perform the opening/closing operation simultaneously with each other or individually, respectively. Even in a case in which the plurality of developing devices are connected to the developer recovery device as described above, the developing system can allow the shutters to appropriately perform opening/closing operations.

FIG. 1 is a diagram illustrating the schematic structure of an example imaging apparatus 1 including a recording medium conveying unit 10, a transfer unit 20, photoreceptor drums 30, four developing devices 100, and a fixing unit 40.

The recording medium conveying unit 10 stores sheets P as recording mediums on which images are to be finally formed. Further, the recording medium conveying unit 10 conveys the sheets P onto a recording medium-conveying path. The sheets P are stacked in a cassette. The recording medium conveying unit 10 allows a sheet P to reach a secondary transfer region R at a timing when toner images to be transferred to the sheet P reach the secondary transfer region R.

The transfer unit 20 conveys toner images, which are formed by the photoreceptor drums 30, to the secondary transfer region R where the transfer unit 20 secondarily transfers the toner images to the sheet P. The transfer unit 20 includes: a transfer belt 21;

suspension rollers

21a, 21b, 21c, and 21d that suspend the transfer belt 21; primary transfer rollers 22 that hold the transfer belt 21 together with the photoreceptor drums 30; and a secondary transfer roller 24 that holds the transfer belt 21 together with the suspension roller 21d.

The transfer belt 21 is an endless belt that is rotationally moved by the

suspension rollers

21a, 21b, 21c, and 21d. The primary transfer rollers 22 are provided so as to press the photoreceptor drums 30 from the inner peripheral side of the transfer belt 21. The secondary transfer roller 24 is provided so as to press the suspension roller 21d from the outer peripheral side of the transfer belt 21. Further, the transfer unit 20 may further include a belt cleaning device that removes toner adhering to the transfer belt 21, and the like.

The photoreceptor drum 30 is an electrostatic latent image carrier which an image is to be formed on the peripheral surface thereof. The photoreceptor drum 30 is formed of, for example, an organic photoconductor (OPC). The imaging apparatus 1 may comprise an apparatus that can form a color image. In the imaging apparatus 1, the four photoreceptor drums 30 are provided along the moving direction of the transfer belt 21 so as to correspond to the respective colors, that is, for example, yellow, magenta, cyan, and black. As illustrated in FIG. 1, a charging roller 32, an exposure unit 34, the developing device 100, and a cleaning unit 38 are provided on the periphery of each photoreceptor drum 30.

The charging roller 32 uniformly charges the surface of the photoreceptor drum 30 to a predetermined potential with electricity. The exposure unit 34 exposes the surface of the photoreceptor drum 30, which is charged with electricity by the charging roller 32, according to the image to be formed on the sheet P. Accordingly, the potential of a portion, which is exposed by the exposure unit 34, of the surface of the photoreceptor drum 30 is changed and an electrostatic latent image is formed. Toners are supplied to the four developing devices 100 from toner tanks 36 that are provided so as to correspond to the respective developing devices 100. The developing device 100 develops the electrostatic latent image, which is formed with toner on the photoreceptor drum 30, to generate a toner image. The four toner tanks 36 are filled with developers to be supplied in which a yellow toner, a magenta toner, a cyan toner, and a black toner are mixed with a carrier, respectively.

The cleaning unit 38 recovers the toner that remains on the photoreceptor drums 30 after the toner image formed on the photoreceptor drum 30 is primarily transferred to the transfer belt 21. For example, a structure in which a cleaning blade is in contact with the peripheral surface of the photoreceptor drum 30 to remove the toner remaining on the photoreceptor drum 30 can be employed as the cleaning unit 38. Meanwhile, an electricity removal lamp, which resets the potential of the photoreceptor drum 30, can also be disposed on the periphery of the photoreceptor drum 30 between the cleaning unit 38 and the charging roller 32 in the rotation direction of the photoreceptor drum 30.

The fixing unit 40 allows the toner images, which are secondarily transferred to the sheet P from the transfer belt 21, to adhere and to be fixed to the sheet P. The fixing unit 40 includes, for example, a heating roller 42 and a pressure roller 44. The heating roller 42 is a cylindrical member that can be rotated about a rotation axis thereof. For example, a heat source, such as a halogen lamp, is provided in the heating roller 42. The pressure roller 44 is a cylindrical member that can be rotated about a rotation axis thereof. The pressure roller 44 is provided so as to press the heating roller 42. For example, a heat-resistant elastic layer, such as silicone rubber, is provided on the outer peripheral surface of each of the heating roller 42 and the pressure roller 44. In a case in which the sheet P passes through a fixing nip portion that is a contact region between the heating roller 42 and the pressure roller 44, the toner images are melted and fixed to the sheet P.

Further, the imaging apparatus 1 is provided with

discharge rollers

52 and 54 that are used to discharge the sheet P to which the toner image is fixed by the fixing unit 40 to the outside of the apparatus.

Next, an example operation of the imaging apparatus 1 will be described. Image signals of an image to be recorded are input to the imaging apparatus 1. A controller of the imaging apparatus 1 uniformly charges the surfaces of the photoreceptor drums 30 to a predetermined potential with electricity by the charging rollers 32 on the basis of the received image signals. Then, the controller of the imaging apparatus 1 allows the exposure unit 34 to irradiate the surfaces of the photoreceptor drums 30 with laser beams to form electrostatic latent images.

The developing device 100 adjusts the toner and the carrier so that the toner and the carrier have a suitable mixing ratio, and mixes and stirs the toner and the carrier. Accordingly, the developing device 100 uniformly disperses the toner to adjust the developer and to control the amount of electric charge that is is applied to the developer. The developer is carried by a developing roller 110. Further, in a case in which the developer is conveyed to a region facing the photoreceptor drum 30 by the rotation of the developing roller 110, the toner contained in the developer carried by the developing roller 110 is moved to the electrostatic latent image formed on the peripheral surface of the photoreceptor drum 30 and the electrostatic latent image is developed. A toner image, which is formed in this way, is primarily transferred to the transfer belt 21 from the photoreceptor drum 30 in a region where the photoreceptor drum 30 and the transfer belt 21 face each other. Toner images, which are formed on the four photoreceptor drums 30, are sequentially stacked on the transfer belt 21, so that one stacked toner image is formed. Then, the stacked toner image is secondarily transferred to the sheet P, which is conveyed from the recording medium conveying unit 10, in the secondary transfer region R where the suspension roller 21d and the secondary transfer roller 24 face each other.

The sheet P to which the stacked toner image is secondarily transferred is conveyed to the fixing unit 40. The sheet P is allowed to pass while heat and pressure are applied to the sheet P between the heating roller 42 and the pressure roller 44, so that the stacked toner image is melted and fixed to the sheet P. After that, the sheet P is discharged to the outside of the imaging apparatus 1 by the

discharge rollers

52 and 54. Meanwhile, in a case in which the transfer unit 20 includes a belt cleaning device, the toner remaining on the transfer belt 21 is removed by the belt cleaning device after the stacked toner image is secondarily transferred to the sheet P.

The schematic structure of the entire developing device 100 will be described with reference to FIG. 1 and FIG. 2. FIG. 2 is a cross-sectional view illustrating the schematic structure of the example developing device 100. The developing device 100 uses a two-component developer, which is formed of a toner and a carrier, as the developer. Further, a so-called trickle developing method is employed in the developing device 100. For an increase in the life of the developer, the developing device 100 discharges an old developer from a developer discharge port and supplies a new developer into a developer storage chamber.

In some examples, the developing device 100 includes the developing roller 110, a first conveying member (conveying member) 120, and a second conveying member (conveying member) 130. The developing roller 110, the first conveying member 120, and the second conveying member 130 are provided in a developer storage chamber 160 that is formed by a case 150 of the developing device 100.

The developing roller 110 is a developer carrier that supplies a toner to the electrostatic latent image formed on the peripheral surface of the photoreceptor drum 30.

Air may be taken into the developer storage chamber 160 by the rotation of the developing roller 110 such that the pressure in the case 150 rises. The case 150 may be provided with a pressure-release hole 150a to release pressure in the case 150. The pressure-release hole 150a may be covered with a filter 101 so that a developer is not discharged. Meanwhile, a position where the pressure-release hole 150a is provided is not limited to the position illustrated in FIG. 2, and the pressure-release hole 150a can be provided at other positions.

The first and second conveying

members

120 and 130 stir the carrier as a magnetic material and the toner as a non-magnetic material, which form the developer, in the developer storage chamber 160 to charge the carrier and the toner with electricity through friction.

The case 150 includes a first case portion 151 and a second case portion 152. The first case portion 151 stores the developing roller 110 and the first conveying member 120. The second case portion 152 stores the second conveying member 130.

The first conveying member 120 supplies the developer, which is mixed and stirred, to the developing roller 110. The first conveying member 120 includes a first support shaft 122 and a first conveying blade 124. The first support shaft 122 is rotatably supported by the first case portion 151. The first conveying blade 124 is provided on the outer peripheral surface of the first support shaft 122. The first conveying blade 124 includes a spiral inclined surface that is disposed along the longitudinal direction of the first support shaft 122.

The second conveying member 130 functions to mix and stir the developer to sufficiently charge the developer with electricity. The second conveying member 130 conveys the developer, which is charged with electricity, to the first conveying member 120. As in the case of the first conveying member 120, the second conveying member 130 includes a second support shaft 132 and a second conveying blade 134. The second support shaft 132 is rotatably supported by the second case portion 152. The second conveying blade 134 is provided on the outer peripheral surface of the second support shaft 132. The second conveying blade 134 includes a spiral inclined surface that is disposed along the longitudinal direction of the second support shaft 132.

The first and second conveying

members

120 and 130 are arranged side by side so that the first and

second support shafts

122 and 132 are substantially parallel to each other. The first and

second case portions

151 and 152 are provided adjacent to each other in a substantially vertical direction. In some examples, the lower portion of the first case portion 151 and the upper portion of the second case portion 152 are formed of one member (hereinafter, referred to as a "partition plate 106"). That is, the partition plate 106 also functions as a part of the first case portion 151 and a part of the second case portion 152. The partition plate 106 partitions the first and second conveying

members

120 and 130. The partition plate 106 is provided with a first opening portion 106a and a second opening portion 106b.

The first opening portion 106a allows a developer to be delivered into the second case portion 152 from the inside of the first case portion 151. The second opening portion 106b allows a developer to be delivered to the first case portion 151 from the second case portion 152.

The developer, which is conveyed while being stirred by the second conveying member 130 in the second case portion 152, is sent into the first case portion 151 through the second opening portion 106b. The first conveying blade 124 of the first conveying member 120 conveys the developer toward the first opening portion 106a from the second opening portion 106b while stirring the developer. While the developer is conveyed by the first conveying member 120, a part of the developer is moved to the peripheral surface of the developing roller 110. The residual developer, which is not moved to the peripheral surface of the developing roller 110, is sent into the second case portion 152 through the first opening portion 106a.

The second case portion 152 is provided with a developer supply port 152a. A developer (a toner and a carrier) to be supplied is supplied into the second case portion 152 through the developer supply port 152a.

The first case portion 151 is further provided with a developer discharge port H. The developer discharge port H discharges the developer, which has deteriorated due to a printing operation, to the outside of the developing device 100 by using a change in the volume of the developer in the developer storage chamber 160. Specifically, an end portion of the first conveying member 120, which is close to the developer discharge port H, is provided with a counter blade 126 and a discharge blade 128. The counter blade 126 is provided at a position between the first opening portion 106a and the developer discharge port H. The counter blade 126 is provided on the outer peripheral surface of the first support shaft 122. The counter blade 126 includes a spiral inclined surface that is disposed along the longitudinal direction of the first support shaft 122.

The counter blade 126 conveys the developer in a direction opposite to a direction in which the first conveying blade 124 conveys the developer. For example, the counter blade 126 pushes the developer, which is conveyed toward the developer discharge port H from the first opening portion 106a, in a backward direction.

The discharge blade 128 is provided at a portion that is closer to the developer discharge port H than the counter blade 126. The discharge blade 128 is provided on the outer peripheral surface of the first support shaft 122. The discharge blade 128 includes a spiral inclined surface that is disposed along the longitudinal direction of the first support shaft 122. The discharge blade 128 conveys the developer the same direction as a direction in which the first conveying blade 124 conveys the developer. For example, the discharge blade 128 conveys the developer toward the developer discharge port H from the first opening portion 106a.

In some examples, the counter blade 126 pushes the developer back toward the first conveying blade 124 so that the developer stored in the developer storage chamber 160 is not moved toward the developer discharge port H. In a case in which the amount of the developer stored in the developer storage chamber 160 is increased, the developer goes over the counter blade 126. The developer, which goes over the counter blade 126, is conveyed toward the developer discharge port H by the discharge blade 128.

The end portion of the first case portion 151 at which the developer discharge port H is formed is formed in a substantially cylindrical shape. A portion of the first case portion 151 at which the developer discharge port H is formed is referred to as an insertion portion 155.

Further, as illustrated in FIG. 3, the example imaging apparatus 1 of FIG. 1 includes a developer recovery device 200 that recovers the developer. The developer recovery device 200 recovers the developer discharged from the developer discharge port H of the developing device 100 in a state in which the developing device 100 is connected to the developer recovery device 200. As described above, the developing devices 100 and the developer recovery device 200 form a developing system that recovers the developer, which is discharged from the developing devices 100 in a state in which the developing devices 100 are connected to the developer recovery device 200, to the developer recovery device 200.

In some examples, the insertion portion 155 of the developing device 100 is inserted into a corresponding insertion hole 210 of the developer recovery device 200, so that the developing device 100 is connected to the developer recovery device 200. The structure of a portion around a connecting portion (a portion around the developer discharge port H) between the developing device 100 and the developer recovery device 200 will be described below.

FIG. 4 is a schematic diagram illustrating a connecting portion between the developing device 100 and the developer recovery device 200 of FIG. 3 in a first operating position. FIG. 5 is a schematic cross-sectional view of the connecting portion between the developing device 100 and the developer recovery device 200 of FIG. 4. In some examples, FIGS. 4 and 5 may be understood to illustrate a case in which a shutter 170 is in a closed state in a state in which the developing device 100 is connected to the developer recovery device 200. As illustrated in FIGS. 4 and 5, the annular shutter 170 is mounted on the insertion portion 155 of the developing device 100. The shutter 170 includes an annular shutter-body portion 171 and a protrusion 172 that extends along a circumferential direction from the outer peripheral surface of the shutter-body portion 171. The shutter-body portion 171 is provided so as to surround the outer peripheral surface of the insertion portion 155.

The shutter 170 is provided so as to be slidable relative to the insertion portion 155 along the direction of the axis of the insertion portion 155 (the direction of the axis of the first support shaft 122). Since the shutter 170 is slidable, the shutter-body portion 171 can cover the developer discharge port H provided at the insertion portion 155. That is, the shutter 170 can adjust the opening area of the developer discharge port H by performing a slide operation (opening/closing operation). Meanwhile, the shutter 170 may be made to slide by a mechanism (not illustrated) to allow the developer discharge port H to be in a closed state in a state in which the developing device 100 is not connected to the developer recovery device 200.

When the developing device 100 is connected to the developer recovery device 200, a part of the shutter 170 is inserted into the insertion hole 210 of the developer recovery device 200 together with the insertion portion 155. When the developing device 100 is inserted into the developer recovery device 200, the protrusion 172 of the shutter 170 is in contact with the edge portion of the insertion hole 210. In a state in which the developing device 100 is inserted into the developer recovery device 200, the shutter 170 covers the developer discharge port H. Meanwhile, although not illustrated in FIGS. 4 and 5, a sealing member may be provided so that a developer does not leak from a gap between the insertion hole 210 and the insertion portion 155 (shutter 170).

As illustrated in FIG. 5, a storage portion (first storage portion) 180 is provided in the insertion portion 155. In some examples, the inner wall of the insertion portion 155 is dented outward, so that the storage portion 180 is formed. The developer discharge port H communicates with the storage portion 180. The storage portion 180 temporarily stores the developer that is discharged to the outside of the developing device 100 through the developer discharge port H. The developer discharge port H discharges the developer, which is temporarily stored in the storage portion 180, to the outside of the developing device 100. In this way, the storage portion 180 stores the developer, which is discharged from the developer discharge port H, at a position on the upstream side of the developer discharge port H in a discharge direction.

The storage portion 180 is provided with a storage-amount detection sensor S that detects the amount of the developer stored in the storage portion 180.

The developer recovery device 200 is provided with a drive mechanism 220 that allows the shutter 170 to slide (opening/closing operation). The drive mechanism 220 adjusts the opening area of the developer discharge port H by allowing the shutter 170 to perform the opening/closing operation in a state in which the developing device 100 is connected to the developer recovery device 200. For example, as illustrated in FIG. 4, the drive mechanism 220 includes a cam 221 and a drive unit 222 that controls the driving of the cam.

The cam 221 is mounted on the outer surface of the developer recovery device 200, and is rotated about a rotating shaft 221a by the drive unit 222. As illustrated in FIGS. 4 and 6, the tip portion of the cam 221 biases the protrusion 172 of the shutter 170 by the rotation of the cam. Accordingly, the shutter 170 is allowed to slide. The shutter 170 is allowed to slide by the rotation of the cam 221 and the opening area of the developer discharge port H is changed as illustrated in FIGS. 5 and 7.

The drive unit 222 includes a driving source (for example, a motor or the like) that drives the cam 221 and a controller that controls the driving source. The driving source may be common to a driving source that rotates the first conveying member 120 or the like, and may be provided for exclusive use to drive the cam 221. The drive unit 222 may be provided with a one-way clutch, an electromagnetic clutch, or the like to drive the cam 221.

In some examples, the drive mechanism 220 switches the open/closed state of the shutter 170 to a developer non-discharge mode and a developer discharge mode by driving the cam 221. The developer non-discharge mode is a mode in which the opening area of the developer discharge port H is set to a first opening area as illustrated in FIGS. 4 and 5 in a state in which the developing device 100 is connected to the developer recovery device 200. In some examples, the first opening area is zero and the developer discharge port H is closed by the shutter 170. The first opening area in the developer non-discharge mode is set to zero, but may correspond to a state in which the developer discharge port H is not completely closed by the shutter 170.

FIG. 6 is a schematic diagram illustrating the connecting portion between the developing device 100 and the developer recovery device 200 of FIG. 3 in a second operating position. FIG. 7 is a schematic cross-sectional view of the connecting portion between the developing device 100 and the developer recovery device 200 of FIG. 6. The developer discharge mode is a mode in which the opening area of the developer discharge port H is set to a second opening area larger than the first opening area as illustrated in FIGS. 6 and 7 in a state in which the developing device 100 is connected to the developer recovery device 200. In some examples, the second opening area is the area of the developer discharge port H, and corresponds to a state in which the developer discharge port H is not covered with the shutter 170 at all. However, the second opening area in the developer discharge mode may be smaller than the opening area of the developer discharge port H. That is, in the developer discharge mode, a part of the developer discharge port H may be covered with the shutter 170.

Since the developer discharge port H is closed by the shutter 170 in the developer non-discharge mode as illustrated in FIG. 5, the developer is not discharged from the developer discharge port H. The developer, which is conveyed toward the developer discharge port H over the counter blade 126, is stored in the storage portion 180. As illustrated in FIG. 7, in the developer discharge mode, the shutter 170 slides so that the developer discharge port H is in an open state, and the developer stored in the storage portion 180 and the developer conveyed toward the developer discharge port H over the counter blade 126 are discharged into a recovery space L of the developer recovery device 200.

Here, the rotational speeds of the first and second conveying

members

120 and 130 in the developer discharge mode are denoted by V1, and the rotational speeds of the first and second conveying

members

120 and 130 in the developer non-discharge mode are denoted by V2. The rotational speeds of the first and second conveying

members

120 and 130 are controlled so that an expression of "V1 ≤ V2" is satisfied. Further, the drive mechanism 220 switches the open/closed state of the shutter 170 to the developer discharge mode and the developer non-discharge mode so that the expression is satisfied. In a case in which the rotational speed of the first conveying member 120 or the like in the developer discharge mode is set to be lower than the rotational speed of the first conveying member 120 in the developer non-discharge mode, the amount of air to be taken into the case 150 by the rotation of the developing roller 110 can be reduced. Accordingly, the flow of air to be generated in the case 150 can be suppressed. Meanwhile, V1 and V2 denote the rotational speeds of the first and second conveying

members

120 and 130, but the rotational speed of any one of the first and second conveying

members

120 and 130 may be used.

In a case in which the amount of the stored developer exceeding a reference value is detected by the storage-amount detection sensor S in the developer non-discharge mode, the drive mechanism 220 switches the shutter 170 to the developer discharge mode from the developer non-discharge mode. As described above, the drive mechanism 220 may allow the shutter 170 to slide (opening/closing operation) on the basis of the detection result of the storage-amount detection sensor S.

In a case in which the developing device 100 is changed to a drive stop state from a drive state, the drive mechanism 220 may allow the shutter 170 to slide so that the opening area of the developer discharge port H is larger than the opening area of the developer discharge port H obtained immediately before the developing device 100 stops driving. For example, in a case in which the developing device 100 is changed to a drive stop state from a drive state, the drive mechanism 220 may switch the shutter 170 to the developer discharge mode from the developer non-discharge mode.

In a case in which the developing device 100 starts driving, the drive mechanism 220 may allow the shutter 170 to slide so that the opening area of the developer discharge port H is smaller than the opening area of the developer discharge port H obtained at the time of stop of the driving of the developing device 100. For example, in a case in which the developing device 100 is changed to a drive state from a drive stop state, the drive mechanism 220 may switch the shutter 170 to the developer non-discharge mode from the developer discharge mode.

Meanwhile, a plurality of developing devices 100 may be connected to the developer recovery device 200. In some examples, the four developing devices 100 corresponding to the respective colors, that is, yellow, magenta, cyan, and black may be connected to the developer recovery device 200. In some examples, the shutter 170 and the drive mechanism 220 are provided for each of the plurality of developing devices 100. Further, the plurality of drive mechanisms 220 can allow the respective shutters 170 to slide simultaneously with each other or individually.

In some examples, the developing system can allow the shutters 170 to perform opening/closing operations even in a state in which the developing devices 100 are connected to the developer recovery device 200. For example, the opening areas of the developer discharge ports H may be adjusted according to the operating states of the developing devices 100, and in order to adjust the opening areas of the developer discharge ports H according to various situations. The developing system can suppress the excessive discharge of the developer from the developing devices 100, which occurs with the flow of air, by adjusting the opening areas of the developer discharge ports H as described herein.

The developing device 100 is provided with the storage portion 180 that stores a developer at a position on the upstream side of the developer discharge port H in the discharge direction. In some examples, the developer can be temporarily stored in the storage portion 180 before being discharged from the developer discharge port H. Accordingly, even in a case in which the developer discharge port H is closed by the shutter 170 (the opening area is small), the clogging of the case 150 of the developing device 100 with the developer can be suppressed. Therefore, rotation of the first conveying member 120 and the like may be maintained.

The drive mechanism 220 can switch the open/closed state of the shutter 170 to the developer non-discharge mode and the developer discharge mode. In some examples, since the open/closed state of the shutter 170 can be switched to two modes even in a state in which the developing device 100 is connected to the developer recovery device 200, an excessive discharge of the developer from the developing device 100 may be suppressed.

In a case in which the rotational speeds of the conveying members in the developer discharge mode are denoted by V1 and the rotational speeds of the conveying members in the developer non-discharge mode are denoted by V2, "V1 ≤ V2" is satisfied. Here, since much air is taken into the developing device 100 in a case in which the rotational speeds of the first and second conveying

members

120 and 130 are high, the internal pressure of the developing device 100 is increased and it is easy for the developer to be excessively discharged from the developer discharge port H together with the flow of air. Accordingly, the excessive discharge of the developer from the developing device 100 may be suppressed by reducing the opening area of the developer discharge port H in a case in which the rotational speeds of the first conveying member 120 and the like are high.

The drive mechanism 220 allows the shutter to perform an opening/closing operation on the basis of the detection result of the storage-amount detection sensor S. Since the drive mechanism 220 can discharge the developer according to the amount of the stored developer, the clogging of the case 150 of the developing device 100 with the developer is suppressed. Accordingly, a hindrance to the rotation of the first conveying member 120 and the like may also be suppressed.

In a case in which the developing device 100 stops driving, the drive mechanism 220 allows the shutter 170 to perform an opening/closing operation so that the opening area of the developer discharge port H is larger than the opening area of the developer discharge port H obtained immediately before the developing device 100 stops driving. In a case in which the developing device 100 stops driving, the internal pressure of the developing device 100 becomes lower than that in a case in which the developing device 100 is being driven. For this reason, the excessive discharge of the developer together with the flow of air may be suppressed. Accordingly, the developing system can discharge an old developer while suppressing the excessive discharge of the developer by increasing the opening area of the developer discharge port H in a case in which the developing device 100 stops driving.

In a case in which the developing device 100 starts driving, the drive mechanism 220 allows the shutter 170 to perform an opening/closing operation so that the opening area of the developer discharge port H is smaller than the opening area of the developer discharge port H obtained at the time of stop of the driving of the developing device 100. In a case in which the developing device 100 starts driving, the internal pressure of the developing device 100 becomes higher than that in a case in which the developing device 100 is stopping. As a result, the developer may be be excessively discharged together with the flow of air. Accordingly, the developing system can suppress the excessive discharge of the developer by reducing the opening area of the developer discharge port H in a case in which the developing device 100 starts driving.

The case 150 is provided with the pressure-release hole 150a provided with the filter 101. Since an increase in the internal pressure of the case 150 of the developing device 100 can be suppressed, the excessive discharge of the developer from the developing device 100 can be suppressed.

The plurality of developing devices 100 are connected to the developer recovery device 200. Further, the respective drive mechanisms 220 provided in the plurality of developing devices 100 allow the respective shutters 170 to perform opening/closing operations simultaneously with each other or individually. Even in a case in which the plurality of developing devices 100 are connected to the developer recovery device 200 as described above, the developing system can allow the shutters 170 to appropriately perform opening/closing operations.

In some examples, the drive mechanism 220 is provided in the developer recovery device 200, but the drive mechanism 220 may be provided in the developing device 100. Further, in a case in which the drive mechanism 220 allows the shutter 170 to slide to open the developer discharge port H in the developer discharge mode, the drive mechanism 220 may adjust the opening area according to various conditions, such as the rotational speed of the first conveying member 120 and the detection result of the storage-amount detection sensor S. Furthermore, the storage portion 180 may not be provided. Moreover, the drive mechanism 220 may allow the shutter 170 to slide by a mechanism other than a mechanism using the cam 221.

It is to be understood that not all aspects, advantages and features described herein may necessarily be achieved by, or included in, any one particular example. Indeed, having described and illustrated various examples herein, it should be apparent that other examples may be modified in arrangement and detail. For example, FIG. 8 is a schematic cross-sectional view of the connecting portion between another example developing device 100A and an example developer recovery device 200A having a different structures of a storage portion 180 and a shutter 170. As illustrated in FIG. 8, in the developing device 100A located in a first operating position, the tip portion of the insertion portion 155 is provided with a storage portion 180A. That is, the case 150 includes a storage portion 180A in addition to the first case portion 151 that stores the first conveying member 120 and the second case portion 152 that stores the second conveying member 130. The storage portion 180A is a cylindrical member that extends in a vertical direction. Further, the insertion portion 155 is provided with a case opening portion 151b that allows the inside of the storage portion 180A and the inside of the insertion portion 155 to communicate with each other.

A developer, which is conveyed toward the case opening portion 151b in the insertion portion 155, is put into the storage portion 180A through the case opening portion 151b, and is discharged to the outside of the developing device 100A from an opening that is provided at the lower portion of the storage portion 180A. Hereinafter, the opening, which is provided at the lower end portion of the storage portion 180A, is referred to as a developer discharge port H1. The lower end portion of the storage portion 180A is provided with a shutter 170A that covers the developer discharge port H1 so as to be capable of opening and closing the developer discharge port H1. The shutter 170A is a flat plate-like member, and is mounted on the lower end portion of the storage portion 180A so as to be rotatable about a shaft J (see FIGS. 8 to 10).

Further, the developing device 100A includes a drive mechanism 220A that allows the shutter 170A to perform an opening/closing operation. In some examples, the drive mechanism 220A biases the shutter 170A toward the lower end portion of the storage portion 180A by the force of a spring. Since the shutter 170A is pushed against the lower end portion of the storage portion 180A by the drive mechanism 220A, the shutter 170A allows the developer discharge port H to be in a closed state.

In a case in which the developer discharge port H1 is allowed to be in a closed state by the shutter 170A, the developer, which is put into the storage portion 180A from the insertion portion 155 through the case opening portion 151b, is gathered on the shutter 170A. The drive mechanism 220A allows the shutter 170A to be rotated by own weight of the developer that is gathered on the shutter 170A. Here, the drive mechanism 220A allows the shutter 170A to be rotated in a case in which a predetermined amount of the developer (the developer having a predetermined weight) is gathered on the shutter 170A.

In some examples, a portion, which includes the storage portion 180A, the shutter 170A, and the drive mechanism 220A, is inserted into an insertion hole 210A of the developer recovery device 200A in addition to the insertion portion 155. That is, the storage portion 180A and the shutter 170A are positioned in a recovery space L of the developer recovery device 200A.

For example, in a case in which the developer discharge port H1 is allowed to be in a closed state by the shutter 170A as illustrated in FIG. 8, a developer G, which is conveyed by the discharge blade 128 and is put into the storage portion 180A from the case opening portion 151b, is gathered on the shutter 170A. FIG. 9 is a schematic cross-sectional view of the connecting portion between the developing device 100A and the developer recovery device 200A in a second operating position. In a case in which a predetermined amount of the developer G is gathered on the shutter 170A, the drive mechanism 220A allows the shutter 170A to be rotated downward about the shaft J by own weight of the developer G as illustrated in FIG. 9. Accordingly, the developer G, which is gathered in the storage portion 180A, is discharged into the recovery space L of the developer recovery device 200A.

FIG. 10 is another schematic cross-sectional view of the connecting portion between the developing device 100A and the developer recovery device 200A of FIG. 8. In a case in which the developer G gathered in the storage portion 180A is discharged, the drive mechanism 220A allows the shutter 170A return to an original position (a position where the developer discharge port H1 is in a closed state) by the force of the spring as illustrated in FIG. 10. In some examples, the developing device 100A and the developer recovery device 200A form a developing system that recovers the developer, which is discharged from the developing device 100A in a state in which the developing device 100A is connected to the developer recovery device 200A, to the developer recovery device 200A.

As described above, the shutter 170A adjusts the opening area of the developer discharge port H1 by being rotated (opening/closing operation). Further, since the drive mechanism 220A allows the shutter 170A to be rotated (opening/closing operation) by own weight of the developer and the force of the spring, the drive mechanism 220A can switch the shutter 170A to a developer non-discharge mode in which the developer discharge port H1 is allowed to be in a closed state (a state illustrated in FIG. 8) by the shutter 170A and a developer discharge mode in which the developer discharge port H1 is allowed to be in an open state (a state illustrated in FIG. 9).

In some examples, the drive mechanism 220A allows the shutter 170A to be operated by own weight of the developer that is gathered on the shutter 170A. Since a driving source for driving the shutter 170A may be omitted, the developing system can be simplified.

In addition to examples in which the drive mechanism 220A allows the shutter 170A to be rotated by the weight of the developer and the force of the spring, in other examples the drive mechanism 220A may rotate the shutter 170A by a driving source, such as a motor. Additionally, the drive mechanism 220A can allow the shutter 170A to perform an opening/closing operation, for example, at the same timing as the timing of the drive mechanism 220, such as at the time of start of driving of the developing device 100.

Further, the storage portion 180A, the shutter 170A, and the drive mechanism 220A are not limited to a structure in which the storage portion 180A, the shutter 170A, and the drive mechanism 220A are provided in the developing device 100A, and may be provided in the developer recovery device 200A. In some examples, the insertion portion 155 is inserted into the developer recovery device 200A so that the case opening portion 151b of the insertion portion 155 faces the inside of the edge of the upper opening of the storage portion (second storage portion) 180A provided in the developer recovery device 200. Alternatively, the storage portion 180A, the shutter 170A, and the drive mechanism 220A may be provided as members separate from the developing device 100A and the developer recovery device 200A.

Example shutters

In addition to shutters having the shape of a flat plate, other shutter shapes are contemplated herein. For example, as in

shutters

170B and 170C illustrated in FIGS. 11 and 12, the surfaces (the surfaces facing the storage portion 180A) of the

shutters

170B and 170C corresponding to the upstream side in the discharge direction of a developer may be formed in a tapered shape. Here, as illustrated in FIG. 11, the surface of the shutter 170B facing the storage portion 180A is formed in a shape that is bent downward in a "V" shape, in a state in which the developer discharge port H1 is closed by the shutter 170B. Further, as illustrated in FIG. 12, the surface of the shutter 170C facing the storage portion 180A is formed in a shape that protrudes upward (toward the storage portion 180A) in a state in which the developer discharge port H1 is closed by the shutter 170C.

By way of further example, as in

shutters

170D and 170E illustrated in FIGS. 13 and 14, the surfaces (the surfaces facing the storage portion 180A) of the

shutters

170D and 170E corresponding to the upstream side in the discharge direction of a developer may be formed in the shape of a bowl. Here, as illustrated in FIG. 13, the surface of the shutter 170D facing the storage portion 180A is formed in a shape that is curved downward in a state in which the developer discharge port H1 is closed by the shutter 170D. Further, as illustrated in FIG. 14, the surface of the shutter 170E facing the storage portion 180A is formed in a shape that curves upward (toward the storage portion 180A) in a state in which the developer discharge port H1 is closed by the shutter 170E.

Other shapes can be employed as the shape of the shutter. For example, the shape of the shutter may be selected according to the viscosity of a developer, the rate of separation of the developer from the shutter, the tendancy of the developer to adhere to the shutter, and the like. Since various shapes can be employed as the shape of the shutter as described above, the amount of the developer remaining on the shutter can be reduced, that is, the developer can be substantially discharged in a case in which the shutter is in an open state.

List of Reference Numbers

100, 100A: developing device (developing system), 101: filter, 120: first conveying member (conveying member), 130: second conveying member (conveying member), 150: case, 150a: pressure-release hole, 170, 170A to 170E: shutter, 180, 180A: storage portion (first storage portion, second storage portion), 200, 200A: developer recovery device (developing system), 220, 220A: drive mechanism, H, H1: developer discharge port, L: recovery space, S: storage-amount detection sensor.

Claims

A developing system comprising:

a developing device including a case to store a developer;

a developer recovery device to recover the developer while the developer recovery device is connected to the developing device;

a developer discharge port to discharge the developer stored in the case to the developer recover device;

a shutter to adjust an opening area of the developer discharge port by performing an opening/closing operation; and

a drive mechanism to actuate the shutter to perform the opening/closing operation.
The developing system according to claim 1,

wherein the case is provided with a first storage portion to store the developer, which is discharged from the developer discharge port, at a position on an upstream side of the developer discharge port in a discharge direction, and

the developer discharge port to discharge the developer stored in the first storage portion to the developer recovery device.
The developing system according to claim 2, further comprising:

a storage-amount detection sensor to detect the amount of the developer stored in the first storage portion,

the drive mechanism to actutate the shutter to perform the opening/closing operation on the basis of a detected result of the storage-amount detection sensor.
The developing system according to claim 1,

the drive mechanism to actuate the shutter to perform the opening/closing operation in response to a weight of the developer that accumulates on the shutter.
The developing system according to claim 1,

the drive mechanism to actuate the shutter so that the opening area of the developer discharge port is larger than the opening area of the developer discharge port before the developing device stops driving.
The developing system according to claim 1,

the drive mechanism to actuate the shutter so that the opening area of the developer discharge port is smaller than the opening area of the developer discharge port when the developing device stops driving.
The developing system according to claim 1,

wherein a surface of the shutter corresponding to an upstream side in a discharge direction of the developer is formed in a tapered shape, the shape of a bowl, or the shape of a flat plate.
The developing system according to claim 1,

wherein the case is provided with a pressure-release hole to adjust pressure in the case, and

the pressure-release hole is covered with a filter.
The developing system according to claim 1,

wherein a plurality of the developing devices are connected to the developer recovery device,

the shutter and the drive mechanism are provided for each of the plurality of developing devices, and

the plurality of drive mechanisms to actuate the shutters to perform the opening/closing operation simultaneously with each other or individually.
A developing system comprising:

a developing device to discharge a developer;

a developer recovery device including a storage portion to store the developer discharged from the developing device while the developer recovery device is connected to the developing device;

a developer discharge port to discharge the developer stored in the storage portion into a recovery space of the developer recover device;

a shutter to adjust an opening area of the developer discharge port by performing an opening/closing operation; and

a drive mechanism to actuate the shutter to perform the opening/closing operation.
The developing system according to claim 10,

the drive mechanism to switch the shutter to a developer non-discharge mode in which the opening area of the developer discharge port is set to a first opening area while the developing device is connected to the developer recovery device, and to switch the shutter to a developer discharge mode in which the opening area of the developer discharge port is set to a second opening area larger than the first opening area while the developing device is connected to the developer recovery device.
The developing system according to claim 11,

wherein the developing device includes a conveying member that circulates the developer in the developing device, and

the rotational speed of the conveying member in the developer discharge mode is less than or equal to the rotational speed of the conveying member in the developer non-discharge mode.
The developing system according to claim 10, further comprising:

a storage-amount detection sensor that detects an amount of the developer stored in the second storage portion,

the drive mechanism to actuate the shutter to perform the opening/closing operation on the basis of a detected result of the storage-amount detection sensor.
The developing system according to claim 10,

the drive mechanism to actuate the shutter so that the opening area of the developer discharge port is larger than the opening area of the developer discharge port before the developing device stops driving, and

the drive mechanism to actuate the shutter so that the opening area of the developer discharge port is smaller than the opening area of the developer discharge port when the developing device stops driving.
The developing system according to claim 10,

wherein a plurality of the developing devices are connected to the developer recovery device,

the shutter and the drive mechanism are provided for each of the plurality of developing devices, and

the plurality of drive mechanisms to actuate the shutters to perform the opening/closing operation simultaneously with each other or individually.